The present disclosure relates to a laser scanning device and an image forming apparatus including the same.
In general, an image forming apparatus of an electrophotographic system includes a laser scanning device that scans a light beam on a surface of a photoconductor. As the laser scanning device scans the light beam, an electrostatic latent image is written on the surface of the photoconductor.
In the laser scanning device, a scanning mirror such as a polygon mirror reflects the light beam so as to scan the light beam in a main scanning direction. Furthermore, a light sensor disposed on a scanning route of the light beam detects reception of the light beam. In addition, a control portion controls a timing at which the light beam writes the electrostatic latent image, based on a timing at which the light sensor generates a detection signal.
In addition, there is known a configuration where a mask having step-like light shielding portion and light transmission portion is disposed on a route of the light beam moving toward a light receiving surface of a light amount sensor. In this case, by the action of the mask, the amount of light received by the light amount sensor changes in analog depending on the position of the light beam in a sub scanning direction, during a period in which the light beam passes through the light receiving surface.
In a case where the mask is used, an average value of sampling values of detection signals of the light amount sensor indicates an amount of light received by the light amount sensor during the period in which the light beam passes through the light receiving surface.
As a result, a control portion may include a piezo actuator that adjusts the orientation of the mirror that reflects the light beam so that the average value of the sampling values approaches a predetermined target value.